xen/arm: Transitional change to build HAS_VPCI on ARM.

This patch will be reverted once we add support for VPCI MSI/MSIX
support on ARM.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Roger Pau Monné <rogewr.pau@citrix.com>

xen/drivers/vpci/Makefile

@@ -1 +1,2 @@
-obj-y += vpci.o header.o msi.o msix.o
+obj-y += vpci.o header.o
+obj-$(CONFIG_HAS_PCI_MSI) += msi.o msix.o

xen/drivers/vpci/header.c

@@ -96,8 +96,10 @@ static void modify_decoding(const struct pci_dev *pdev, uint16_t cmd,
      * FIXME: punching holes after the p2m has been set up might be racy for
      * DomU usage, needs to be revisited.
      */
+#ifdef CONFIG_HAS_PCI_MSI
     if ( map && !rom_only && vpci_make_msix_hole(pdev) )
         return;
+#endif
 
     for ( i = 0; i < ARRAY_SIZE(header->bars); i++ )
     {

xen/include/asm-arm/pci.h

@@ -26,6 +26,14 @@ struct arch_pci_dev {
     struct device dev;
 };
 
+/* Arch-specific MSI data for vPCI. */
+struct vpci_arch_msi {
+};
+
+/* Arch-specific MSI-X entry data for vPCI. */
+struct vpci_arch_msix_entry {
+};
+
 /*
  * Because of the header cross-dependencies, e.g. we need both
  * struct pci_dev and struct arch_pci_dev at the same time, this cannot be